Means for increasing the speed of boats



Aug. 20, 1929. w. HARPER, JR

"BANS FOR INCREASING THE SPEED O! BOATS Filed April 21, 1927 2Sheets-Sheet 1 v INVENTOR.

WILLIAM HARPER JR.

A TTORNEY Aug. 20, 1929. w. HARPER, JR

HEARS FOR INCRE ASING THE SPEED OF BOATS Filed April 21. 1927 2Sheets-Sheet 2 mmvron ILLIAM HARPER. JR.

ATTORNEY Patented Aug. 20, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM HARPER, IR, 01' PORT WASHINGTON, NEW YORK.

MEANS FOR I NCREABING THE OI BOATS.

Application filed April 81, 1927.

This invention relates to means for increasing the speed of boats byreducing the friction encountered in passing through the water.

An ob'ect of the invention is to distribute a film 0 air uniformly inthin streams over the submerged surfaces of a boat to faciliboat eitherby suction or by suitable blowing apparatus. he air acts as a cushionwhich diminishes the friction of the ,water when the boat is in motion.The various constructions heretofore employed to increase the speed of aboat in this manner have proved inetficient because of their failure todiffuse the air evenly over the entire submerged surface of, the boat,

thereby failin to effect a uniform reduction of water friction. The airhas usually been fed through outlet ports or scales in the hull of theboat without regard to its direction or uniform distribution. Attemptsto su ply air to all parts of the submerged hull liave also frequentlyresulted in emplo ing an excessive numberof projecting out et portswhich offer more resistance to the motion of the boat than an ordinaryplane surface would do.

The difficulties outlined above are largel overcome by the presentinvention whic provides a simple and efiicient construction for laying auniform thin film of air between the water and the submerged hull,rudder and propeller of a boat. This is accomplished by passing the airthrough spaced. rows of uniform delivery orifices which open toward thestern of the boat. In the preferred embodiment of the invention thedelivery orifices comprise small parallel corrugations communicatingwith air intake ports whereby uniform thin streams of air are drawn frombow to stem when the boat is in motion. The novel construction andarrangement of the air delivery orifices results in a more uniformreduction of water friction than heretofore and reduces the necessaryunder-water projecting parts to a minimum.

separated from each lies flush with Serial No. 185,457.

The various features and advantages of the invention will be describedin connection with the accompanying drawings in which similar referencec aracters designate correlsptilndmg parts in the several views, and inw 1c Fig. 1 is an inverted plan view showing the bottom of a speed boatembodying my invention;

Fig. 2- is an elevation showing a series of air tubes communicating withfices in the bottom of. the boat;

Fig. 3 is a detail sectional view showin the construction of air tube,air manifol and delivery'orifice; Fig. 4 is a fragmentarycross-sectional view looking through the hull;

Fig. 5 .is a fragmentary elevation of the livery oristern of theboatshowing the construction of the rudder and screw propeller;

Fig. 6 is a. section through the rudder, taken on the line 66 of Fig. 5;

Fig. 7 is a view of the of the propeller blades; an

Fig. 8 is a section through the propeller blade taken on the line 88 ofFig. 5, showing the air chamber and delivery port.

11 the drawings, the invention is illustrated as applied to a speed boathaving a hull.1 with a substantially flat bottom plank ing 2 and aninterior reinforcing plate 3 of any suitable construction. A step 4 maybe provided near the center of the boat to to the invention.

formly over the bottom of the boat throu h air tubes 5 which project insubstantia y vertical planes above air manifolds 6. The air manifoldsextend transversely across the bottom of the boat and are attached tothe reinforcing plate 3 by means of screws 7. Each air manifold 6communicates through a series of ducts 8 with an air distributor passageor groove 9 extending transversely through the bottom planking 2 underthe air manifold. 1 Continuous metal strips or ribs 10 extendtransversely across the bottom planking 2 immediately under thedistributor rooves 9. These strips or ribs are preferab y narrow, andmay be widely other, as shown in Fig. 1.- The forward end of each rib 10is flat and the bottom planking 2 while upper part of one aid inretaining the air, but is not essential the rear end is crimpcd orserrated to provide a plurality of closely spaced corrugated 'or fluteddelivery orifices 11 which project toward the stern of the boat. Theelongated strips of metal 10 are flexible and may be bent'as required tofit the hull of the boat. The forward fiat or smooth edge of the stripsmay be attached to the bottom planking 2 on one side of the opening 9 inany sultable manner. The corrugations taper toward the attaching edge ofthe strip, and the upper edges or peaks of the corrugations contact withthe bottom planking 2 thereby closing the sides of the air deliveryorifices 11, as shown in Figs. 3 and 4. The corrugations increase therigidity of the strips 10, and serve to bring the converging streams ofair and water into the closest possible proximity in relation to theirrespective areas.

When the boat is in motion the suction caused by the boat gliding overthe water will cause air to be sucked through the air tubes 5, airmanifold 6, ducts 8 and delivery orifices 11. Due to the shape andrelatively close spacing of the delivery orifices 11 the air will emergein strong wedge-like streams and be diffused evenly across the width ofthe boat. The width of the boat varies from bow to stern and the metalribs lOare preferably tapered slightly from how to stern as shownin Fig.1 so that the delivery orifices 11 on each side of the center line willpoint outwardly in substantially parallel planes. In this manner thefilm of air will spread out fan-like and cover the entire under surfaceof the boat following the water lines leaving the various surfaces. Thecorrugations not only direct air evenly under the hull and prevent theair from being forced toward the sides of the boat, but they alsoprevent the water from moving sidewise under the boat which would tendto displace the air film. The strips 10 slope gradually from the frontto the rear edge and hence there are no abrupt projections which mighttend to retard the passage of the boat through the water. The size andrelative spacing of the air manifolds 6 and corrugated metal ribs 10will vary according to circumstances. They are preferably spaced closelyenough together to maintainstrong streams of air from one series ofdelivery orifices to the next so that a uniform thin cushion of air"will envelop the entire submerged surface of the hull. The deliveryorifices may be spaced still further apart on either side of the step 4since the cushion of air will be more readily retained under the steppedportion of the hull and forced toward the stern when the boat is inmotion. The air tubes 5 project high enough above the water line toprevent the ingress of water which rises in the air manifolds and tubeswhen the boat is at rest.

In Figs. 2 and 5 a screw ropeller 12 is shown mounted upon a sha. t 13which is connected with an engine inside the boat. The rudder 14 issupported by therudder post 15 in the usual manner. According to thepresent invention the friction of the water on the rudder is reduced ina manner similar to that described above in connection with the hull.The rudder is provided with an air chamber 16 which communicates withthe outer air through intake ports 17 on both sides of the rudder abovethe water line. The rudder is provided with a curved shield 18 extendinglengthwise of the rudder post and having a series of small fluted air"delivery orifices" 19 disposed in substantially parallel planes andcommunicating with the air chamber 16. The shield 18 may be of anydesired length, depending upon circumstances, but is preferably lonenough to distribute a film of air over t e greater part of thesubmerged sides of the rudder. When the boat is in motion air is suckedthrough the intake ports 17 air chamber 16 and the delivery orifices 19on both sides of the rudder, the air emerging from the orifices 19 instrong wedge-like streams. The air is thus distributed uniformly overthe'submerged surfaces of the rudder.

Uniform streams of air are also distributed over the blades of the screwpropeller 12 as shown in Figs. 5, 7 and 8. A series of small parallelfluted air outlets 20 are provided near the edge of the leading andcompression side of the propeller blades communicating with hollow airchambers 21. A hollow channel 22 extending longitudinally through thepropeller shaft 13 has one end communieating with the air chambers 21and the other end communicating with a suitable intake port (riot shown)inside the boat. When the propeller is turning air is sucked throughchannel 22 and air chambers 21 through the air outlets 20 and isdistributed in a uniform thin film over the entire front faces of thepropeller blades. In this manner, the retarding effect of skin frictionis largely overcome and the efficiency of the propeller is greatelyincreased. The invention is capable of various modifications andadaptations which are not specifically described but are included withinthe scope of the appended claims.

The invention claimed is:

1. The combination with a boat comprising a hull having a bottomsurface, of a plurality of widely separated ribs extending transverselyacross said bottom surface, a plurality of closely spaced corrugationsin said ribs having their forward edges closed and their rear edgesopening toward the stern of the bo at,. and air inlet portscommunicating with said corrugations.

2. The combination with a boat comprising a hull, of a plurality ofcontinuous strips of material extending transversely across the bottomof said hull with their forward edges lying fiat against'the hull andtheir rear edges corrugated to provide a plurality of orifices openingtoward the stern of the boat, air chambers extending transversely acrosssaid hull and communicating with said orifices, and air intake tubesleading from said chambers to the atmosphere.

3. The combination with a boat having a hull, of a plurality of rows ofair delivery orifices extending transversely across said hull, airdistributor grooves formed in said hull and communicating with saiddelivery orifices, air chambers extending transversely across said hulland communicating with said distributor, grooves, and air intake tubesleading from said chambers to the atmosphere.

4. The combination with a boat having a hull, of a strip of materialextending transversely across the hull with its forward edge fiatagainst the hull and its rear portion crimped to provide a plurality ofair delivery orifices opening toward the stern of the boat, and meansfor supplying air to said orifices.

5. The combination with a boat having a hull, of a strip of materialextending transversely across the hull with its forward edge fiatagainst the hull and its rear portion crimped to form small parallelcorrugations providing air delivery orifices opening toward the stern ofthe boat, and an air intake port communicating with a plurality of saidorifices to permit air to be sucked through when the boat is in motion.

6. The combination with a boat having a hull, of a strip of materialextending transversely across the hull with its forward edge flatagainst the hulland its-rear portion crimped to provide a plurality ofair delivery orifices opening toward the stern of the boat, an airdistributor passage formed in the hull above said delivery orifices, andair intake ports communicating with said passage to permit air to besucked through said orifices when the boat is in motion.

7. The combination with a boat having a hull, of a plurality of narrowstrips of metal extending transversely across the hull with theirforward ends flush with the hull and their rear portions corrugated toprovide a "plurality of independent air delivery orifices opening towardthe stern of the boat, air distributor passages extending transverselythrough the hull above said metal strips andcommunicating with the airdelivery orifices therein, air manifolds extending transversely acrossthe inside of the boat above said air distributor passages, a pluralityof spaced ducts extending through the hull and connecting said airdistributor passages to the respective air manifolds, and air tubesleading from said air manifolds to theatmosphere.

. 8. The combination with a boat comprising a hull varying in width frombow to stern, of a plurality of continuous strips of material extendingacross said hull tapering at the center from bow to stern and havingclosely spaced air delivery orifices therein, and air intake portscommunicating with said deliver orifices to permit streams of air to besuc ed fan-like across the hull when the boat is in motion.

9.'The combination with a boat having a hull, of a strip of materialextending across said hull having a multiplicity of closely spaced airdelivery orifices opening toward the stern of the boat with theirforward and side edges closed, and an air passage communicating withsaid orifices to permit air to be sucked through when the boat is inmotion.

10. A device for increasing the speed of boats comprising an elongatedstrip of flexible material having one edge adapted to be transverselyattached to the under surface of a boat and provided with corrugationsrunning transverse to said strip and tapering toward said attaching edgeto provide a series of air passages for drawing air from the interior ofthe boat and discharging it in a film along the bottom of the boatbeyond said strip.

11'. A device for increasing the speed of boats comprising an elongatedstrip of metal adapted to span a transverse opening in the bottom-of'aboat', one edge of said strip being adapted for attachment to the undersurface of the boat on oneside of said opening, and corrugations formedtransversely in said strip tapering toward said attaching'edge tocontact with the surface on the opposite side of said opening to.provide a series of air passages.

Signed at New York, in the county of New York and State of New York,this 14th day of April, A. D. 1927. I

WILLIAM HARPER, JR,

